The present invention relates to the automatic interruption of a device in response to information stored in a storage medium. In particular, the present invention relates to a method and apparatus for automatically interrupting a tape reader for a plurality of preselected time intervals in response to information stored in a storage medium such as a tape.
In recent years, audio-visual performances using multiple slide projectors and other audio-visual aids have become so complex that an electronic means for arranging the projection sequences has become a necessity. Such an electronic means is hereinafter referred to as the programmer.
In general, a programmer may be operated in either a manual or automatic mode. The present invention is directed to the automatic operation of the programmer. When operated automatically, the states of the programmer are determined by a memory storage facility such as a punched tape. Typically, the punched tape may be an eight channel tape which is one inch wide and composed of paper, plastic or combinations thereof. The tape contains the program which determines the sequence of operation of the slide projectors and other audio-visual devices. The tape is provided with one or more holes on each line, hereinafter referred to as a "cue", across the tape width. Each of the holes corresponds to a data channel in the programmer for operating a particular audio-visual device. The data may serve to actuate a projector, a dissolve unit, a light, a tape recorder, and so forth.
The punched tape is fed through an electro-optical tape reader which reads the information on the tape, cue by cue, and transfers the information to the programmer signal processing circuitry. The signal processing circuitry receives the tape reader outputs and generates appropriate electronic signals for controlling the audio-visual devices in accordance with the information on the tape.
Although each cue on the tape contains the necessary information for determining the state of particular audio-visual devices at a given instant of time, it may be required that a particular operating state be maintained for a preselected interval of time. For example, it is often desirable to leave the audio-visual devices in a particular state for a preselected interval of time in order to obtain dramatic effects during an audio-visual show. In addition, the limited cycling times of the audio-visual devices requires that each audio-visual device be permitted to fully cycle before being operated again by the programmer. Moreover, it may be desirable to momentarily interrupt the audio-visual show and fix the states of the audio-visual devices for a preselected interval of time in order to insure audience comprehension of the show.
Prior to the present invention, it was necessary to leave a great number of the cues on a tape blank in order to achieve the required delays. Thus, the tape reader would scan the blank cues without generating any electronic signals at the input of the programmer signal processing circuitry, and the audio-visual devices would not change their states until a cue was reached which contained punched holes. This, however, involves an appreciable waste of tape space.
Although it is known in the prior art to manually interrupt the operation of the tape reader and programmer, manual operation is cumbersome and slow, and it introduces a discontinuity in the general pace of the audio-visual performance.
A primary advantage of the present invention is to automatically interrupt the operation of a device, such as a tape reader, for a plurality of preselected intervals of time.
A further advantage of the present invention is to interrupt the operation of a device such as a tape reader during an audio-visual performance without introducing a discontinuity in the general pace of the performance.
A still further advantage of the present invention to automatically interrupt an audio-visual performance for a plurality of preselected intervals of time without wasting portions of a storage medium such as a tape.
Other advantages will appear hereinafter.